1. Field
The embodiments described below relate to a braking force generation device of a vehicle, and in particular to a braking force generation device that generates a braking force using frictional force generated between a rotary member and a friction member.
2. Description of Related Art
A braking force generation device of a vehicle has a rotary member (e.g., a brake disc) that rotates about a rotational axis along with a wheel, a friction member (e.g., a brake pad) that is supported so as not to rotate about the rotational axis, and a pressing device (e.g., a wheel cylinder). The pressing device includes (i) a stationary member, such as a caliper support member, supported by a knuckle, and (ii) a displacement member (e.g., a caliper and a piston) that slides relative to the stationary member and presses the friction member against the rotary member. Sliding portions of the stationary member and the displacement member are lubricated by a lubricant such as grease.
In the meantime, when a vehicle, such as an automobile, runs, static electricity is generated in the vehicle since air flows while being in friction contact with the vehicle. Also, static electricity is generated, due to each portion of the vehicle's tires having repeated contact with and separation from a road surface as the vehicle's wheels of the vehicle rotate. Further, static electricity is generated due to relative movements of constituent components of an engine and a brake system, for example.
The vehicle is substantially electrically insulated from the ground due to the presence of the tires having a low electric conductivity. Therefore, if static electricity is generated in the vehicle, the vehicle body, for example, is electrostatically charged (generally with positive charges). Since radio noise is likely to be generated if the vehicle body is charged, structures for reducing electric charges carried by the vehicle have been studied, and various structures have been proposed.
For example, one such device is a bearing device having an inner race member, an outer race member, and a plurality of rolling elements interposed between these race members as described in Japanese Patent Application Publication No. 2006-234093 (JP 2006-234093 A). This bearing device has seal devices which each include an elastic member that contacts with one of the race members. Also, the interior of the bearing device is filled with conductive grease.